Modelling Folded Plates for Drawing Output

When creating workshop drawings of folded plate users sometimes notice that the plate seems to be drawn from the “wrong” side. For example, a stair tread seems to be drawn from underneath or a cladding panel is drawn from inside not outside.

This is a common and long-standing issue. It is a result of how the plate is modelled in the first place. The only control a user has over the flat pattern drawing of a folded plate in the drawing or in the DXF file is how they create the plate in the first place. None of the tools for changing the drawing views have any effect on folded plates. The same applies to NC and DXF files.

It is important to note that, even if drawn from the bottom, the flat patterns and DXFs of folded plates are correct. When manufactured as described you will get the correct plate.

Almost the only time it matters which side it is drawn from is when modelling folded Durbar Plate*. Usually, we recommend using Grating objects set to a Checker Plate grating class to model your Durbar plate. However, if you want folds, you cannot do this as grating objects cannot be folded. So, for a durbar folded tread on a stair, you must use folded plate. If you are making folded plate Chequer Plate, it is important that they are manufactured with the dimples are on the correct side.

To be safe, we always recommend placing a note on the drawing to clarify such as “Dimples near side” or “Dimples far side”. However, this cannot be done for NC files and is not practical on DXF files. The best solution is to manage things carefully when modelling.

Contact your local Graitec Advance Workshop representative regarding how to enhance efficiency in your steel and rebar fabrication factory.

How can you ensure you always get your plate drawn from the top?

UCS
If you care about the orientation of the plate in the flat pattern, it is IMPERATIVE that you are paranoid about the UCS at all times when modelling the folded plate.

To ensure that the flat pattern of a folded plate is always drawn from above (dimples near side) then you must create the plate with the UCS appropriate at all times. It is best to model every piece of the folded plate in position with the UCS set as you want to see that piece in the flat pattern. That is similar to how you would set it for a GA view or camera view of the plate with Z pointing up for the flat of a stair tread.

In figure 1 the three folded plates were modelled with the UCS set as per the coloured lines – different for the flat part of each plate.

Figure 1 – Model of folded plates

In Figure 2 you can see the resulting drawings showing that plate 3 is drawn from the underside.

Figure 2 – Drawing of folded plates

There is a Default under Drawing General > General > Detail plates using the CS where the plates were created. Ticking this will possibly change the orientation of the view but will not change the side it is drawn from – see figure 3.

Figure 3 – Draw plates on UCS when created.

Adding Folds

When adding the folds (using Create folded plate without position adjustment) be constantly aware of the main panel of the plate. That should be the biggest panel – usually the flat part of a stair tread. The first plate picked when adding the fold is the main panel.

For example, figure 4 below, if this was a chequer plate stair tread, panel 2 would be the main panel. You should model that with the UCS as shown. To add the folds, select 2 then 1 for the first fold. Then 2 then 3 for the second fold. Finally, 3 then 4 for the third fold. This will keep plate 2 as the main panel. The UCS when plate 2 was created will govern the flat pattern and DXF files and they should be created with the dimples near side. Even then, although drawn from the top you can’t control the rotation of the view and it is not always what you expect.

Figure 4 – Model

Figure 5 – Drawing 

Figure 6 –  DXF File (yellow lines fold down and green fold up).

As you can see both of these are drawn from the top with two down folds.

If you use a stair macro to create the tread of the stair, then they are folded beams not folded plates. Being created by a macro you cannot control how they are created, and they usually do seem to draw from the bottom.  The output is correct for a smooth plate it just doesn’t care what side the dimples are on if you set the material to durbar plate. So, in this case you may have to model the stair manually.

*Durbar Plate, Checker Plate, Chequer Plate, Bulb Plate, Tread Plate etc. are all different names for the same thing for the sake of this blog. In Advance Steel the names Durbar Plate and Checker Plate are used.

Written by Aleck Giles – Software Technical Specialist